Re: [Qemu-devel] [PATCH 3/3] block/ssh: Add basic .bdrv_truncate()

[Richard W.M. Jones]

The series looks fine to me:

  Reviewed-by: Richard W.M. Jones 

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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Re: [Qemu-devel] [PATCH 3/3] block/ssh: Add basic .bdrv_truncate()

[Eric Blake]

On 02/14/2018 02:49 PM, Max Reitz wrote:

libssh2 does not seem to offer real truncation support, so we can only
grow files -- but that is better than nothing.

Signed-off-by: Max Reitz 
---
  block/ssh.c | 24 
  1 file changed, 24 insertions(+)



Reviewed-by: Eric Blake 

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.   +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

[Qemu-devel] [PATCH 3/3] block/ssh: Add basic .bdrv_truncate()

[Max Reitz]

libssh2 does not seem to offer real truncation support, so we can only
grow files -- but that is better than nothing.

Signed-off-by: Max Reitz 
---
 block/ssh.c | 24 
 1 file changed, 24 insertions(+)

diff --git a/block/ssh.c b/block/ssh.c
index ff8576f21e..c235eec255 100644
--- a/block/ssh.c
+++ b/block/ssh.c
@@ -1219,6 +1219,29 @@ static int64_t ssh_getlength(BlockDriverState *bs)
 return length;
 }
 
+static int ssh_truncate(BlockDriverState *bs, int64_t offset,
+PreallocMode prealloc, Error **errp)
+{
+BDRVSSHState *s = bs->opaque;
+
+if (prealloc != PREALLOC_MODE_OFF) {
+error_setg(errp, "Unsupported preallocation mode '%s'",
+   PreallocMode_str(prealloc));
+return -ENOTSUP;
+}
+
+if (offset < s->attrs.filesize) {
+error_setg(errp, "ssh driver does not support shrinking files");
+return -ENOTSUP;
+}
+
+if (offset == s->attrs.filesize) {
+return 0;
+}
+
+return ssh_grow_file(s, offset, errp);
+}
+
 static BlockDriver bdrv_ssh = {
 .format_name  = "ssh",
 .protocol_name= "ssh",
@@ -1231,6 +1254,7 @@ static BlockDriver bdrv_ssh = {
 .bdrv_co_readv= ssh_co_readv,
 .bdrv_co_writev   = ssh_co_writev,
 .bdrv_getlength   = ssh_getlength,
+.bdrv_truncate= ssh_truncate,
 .bdrv_co_flush_to_disk= ssh_co_flush,
 .create_opts  = _create_opts,
 };
-- 
2.14.3